My lowest panel is changing from the editor window to the rendered view
It turns out the problem was that I had a combination of two issues.

Firstly, I have about 3 minutes of blank video so rather than showing black the preview window shows the gray background that is throughout Blender. This made me assume it wasn't working because it was not black, but really it was just transparent.

Secondly, I set it again, then left to make dinner. Turns out it takes a long time to start up (I guess). I've watching it right now and it is creating the video at about 2/3 speed of original footage in the preview. This is largest video in blender by about double in time and also my first 1080 rather than 720. I guess I was just too impatient.  

The important thing is I learned some stuff today. :)